<!DOCTYPE html>
<html lang="en">
	<head>
		<meta charset="UTF-8">
		<meta http-equiv="X-UA-Compatible" content="IE=edge">
		<meta name="viewport" content="width=device-width, initial-scale=1.0">
		<title>Document</title>
	</head>
	<body>
		<script>
			//9. 判断一句话是否以句号结尾。
			let str = window.prompt('请输入一句话');
			// let reg = /。$/;
			// if(reg.test(str)){
			//     console.log('以句号结尾');
			// }else{
			//     console.log('不是以句号结尾');
			// }

			if (str.substring(str.length - 1) == "。") {
				console.log('以句号结尾');
			} else {
				console.log('不是以句号结尾');
			}
		</script>
	</body>
</html>
